Automatic or semiautomatic telephone exchange system



July 7, 1931. E. P. G. WRIGHT AUTOMATIC OR SEMIAUTOMATIC TELEPHONE EXCHANGE SYSTEM Filed Jan. 23, 1930 2 Sheets-Sheet l Human-unmann- INVENTOR ESMOND RG.WR|GHT BY; 7% a ATTORNE July 7, 1931.

E. P. G. WRIGHT AUTOMATIC OR SEMIAUTOMATIC TELEPHONE 1EXCHANGE SYSTEM Filed Jan. 25. 1930 2 Sheets-Sheet 2 T H r m R Y RW M WC R m m D 63 P ll M m HIUUUHZUHZUHZU lm 83 m NODN 8.5 Lm 0N Norm llllfil Fl .1 J

rm Nu -l||||| IT A llll ill) Patented July 7, 1931 1 UNITED :srArEs arrica EsMoNnrn'ILir' GOODWIN was-rem, or .ALZDWYOH, LONDON, ENGLAND, AssiGNoR To INTEENATIONAI STANDARD ELECTRIC OORPOEATIoN, OF NEW YORK, N. Y.

AUTOMATIC on IsEMIAUT'oMATic TELEPHONE EXCHANGE sYsTEM Application med ianuar hs, 1930, serial No. 422,803, and in Great Britain February 7, 1929.

The present invention relates to auto matic and semi-automatic telephone systoms and is more particularly intended for use with testing arrangements.

It the usual practice in automatic and semiautomatic telephone exchanges to provide final selectors having access to groups of subscribers lines and which are set apart for the use of test clerks. To obtain access to the testing finalselector, jacks are provided at the test clerks, positions giving access to trunks extending to selectors, known as test distributors, which in response to transmitted impulses give access to required testing final selectors and like ordinary fin-a1 selectors do not hunt.

It has also been proposed to control the operation of the ordinary conversation switches in an automatic exchange by means of control circuits common to a plurality of switches.

It is the object of this invention to apply the abovementioned method of control to the special switches which are used by a test clerk in extending a testing connection to a subscriber's line on which it is required to effect certain well known tests.

According to one feature of the invention a plurality of test distributor switches adapted to select a test final switchgiving access to subscribers lines have. associated therewith a control circuit which is adapted to be operatively associated with any one of said distributor switches and which in response to impulses transmitted by a test clerk control the selective opeartion of the predetermined distributor switch.

In accordance with a further feature of the invention a plurality of testing final switches which are adapted to set up a test connection to a subscribers line to be tested have associated therewith a control circuit which is adapted to be operatively associated with any one of said testing final switches and, which in response to impulses transmitted by a test clerk controls the selective operation of a predetermined testing final switch. 1

The invention will be better understood from the following description taken in conjunction with the accompanying drawings in which Figure 1 shows above the broken line a test distributor switch of thesin'glemotion homing type and .below the broken line a controlcircuit common to a plurality of test distributors and comprising agrou-p marking switch lTC and a units marki-n switch lUC.

Figure 2 shows above the broken line a testing final switch of the single-motion homing type and below the broken line .-'a control circuit common to a plurality of testing final switches and comprising a tens marking switch 2TC and a units marking switch 2UC.

The test distributor switches terminate at the wire chieis position, the idle condition of a test distributor switch being predeter mined by the potential on the test wire When a test operator takes into use an idle test distributor switch a circuit is closed for the relays 1K and 12 over ground placed on the test wire by the wire chief through both windings of the relay 1K in parallel through the wiper N2 and home position of the distributor switch, contacts 1 of relay 18 normal, relay 12 and battery. A non-inductive winding of relay 12 is also connected to contacts 1 of relay 18 over contacts 1 of relay 12 normal, and wipers 1T'C2 and 1UC2 of theswitch lTC and 1UC in their normal positions. The relay 1K will not operate in series with the inductive winding of the relay 12 but only in series with the non-inductive winding which is '01 low resistance. The test wire will not, therefore, appear free unless the test distributor'and the marking switches lTC and lUC are in their home positions. When relay 12 operates it opens the circuit to its non-inductive winding. Relay 1K in *operating closes a locking circuit at contacts 1 to make it circuit independent of the home position of the switch. A circuit is completed through a loop under the control of the wire chief from battery and. winding of the relay 1A, contacts 2 of the relay Bit normal, over the loop, contacts 1 of relay RR normal, winding of relay PC to ground causing the operation of both these relays,

Relay 1B is operated by the obvious circuit and when the impulsing takes place a circuit is completed from ground, contacts 1 of relay 1A normal, contacts 3 of relay 1B operated, contacts 3 of relay 1K operated, the winding of relay 13, contacts 5 of relay 15 normal, to the magnet lTC and battery causing the group marking switch to step in accordance with the first series of impulses. Relays 1B and 13 are of the slow releasing type and do not respond to impulsing. Relay 13 completes a circuit for the distributor magnet S through its int-errupter springs, contacts 2 of relay 1B operated, contacts 2 of relay 1K operated, contacts 1 of relay 16 normal, contacts 2 of re lay 13 operated to ground. The switch will continue stepping until it reaches the contact marked by the ground from contacts 4 of relay 16 normal, the wiper and contact of bank lTCl of the switch 1T0, the control wiper C, contacts 5 of relay 1K operated, contacts 3 of relay 16 normal, to relay 16 and battery. Relay 16 will operate to open the driving circuit at contacts 1 of relay 16 but will not lock up. In this way the distributor is unable to proceed beyond the impulses registered in the switch 1T0. Relay 13 also completes the circuit for a partial operation of relay 15 through contacts 3 of relay 15 normal, contacts 1 of relay 13 operated to ground. lVhen the relay 13 restores at the end of the digit, relay 15 operates fully due to the short circuit having been removed from its second winding, over contacts 1 of relay 15 operated to ground at contacts 2 of relay 12 operated. hen relay 15 operates fully a locking circuit is provided for relay 16 through contacts 4 of relay 15 to ground atcontacts 2 of relay 12. The second set of impulses is passed through contacts 5 of relay 15 operated to the switch lUC and when relay 13 reoperates a circuit for the partial operation of relay 17 is established to contacts 2 of relay 17 normal, contacts 3 of relay 15 operated to contacts 1 of relay 13 operated to ground. lV-lien relay 13 restores a second time relay 17 operates fully over both windings in series, contacts 3 of relay 17 operated, contacts 2 of relay 12 operated and ground. The driving circuit for the distributor is recompleted over contacts 1 of relay 16 operated, contacts 1 of relay 17 operated, contacts 2 of relay 18 normal to ground. At the same time the marking ground is extended through contacts 4 of relay 16 operated, contacts 5 of relay 17 operated, the wiper 1UC1 of the switch lUC to the control wiper C, contacts 5 of relay 1K operated, contacts 3 of relay 16 operated to the winding of relay 18 and battery. \Vhen the relay 18 operates the driving circuit for the magnet S is opened at contacts 2 and contacts 3 open the energizing circuit of relay E which was operated through contacts 4 of relay 1K operated and contacts 4 of relay 17 when the latter relay operated. Relay E is of the slowto-release type and does not release immediately the relay 18 operates: contacts 1 of relay 18 open the circuit of relay 1K which releases immediately and also relay 12 which releases slowly. When the relay 12 is released the locking circuit of relays 15, 16 and 17 is opened and the homing circuitot the switch lUC closed through its homing wiper 1UC3. \Vhen the switch lUC reaches home position the" homing circuit for the switch 1TC is also completed over wipers 1TC3 and 1UC3. When the relay E operated a circuit was established for the relay TD through contacts 1 of relay E operated and contacts 3 of relay RR normal. Relay TD is of the slow releasing type and does not release immediately after relay E so that a circuit is establishedfrom battery from one winding of the relay PP, contacts 3 of relay TD operated, contacts 2 of relay E normal contacts 5 of relay RR to ground. Relay PP is of the slow operating type and at the same time a circuit is established for relay RR through contacts 3 of relay E normal, contacts 4 of relay TD operated, contacts 2 of relay PP normal, to the wiper P2 and the test final selector. which will be characterized by a battery potential it that circuit and its associated control are both free. It the test final is engaged the ground on wiper P2 will operate relay RR which will reverse battery at contacts 1 and 2 to signal the wire chief and open the circuit of relay PP before that relay has time to operate. If relay RR does not operate the relay PP will operate, as already described, and lock up over its second winding, contacts 1 of relay PP operated to ground at contacts 4 of relay 1B operated. Contacts 4 of relay PP will change over the circuit for relay RR, to the wiper Pl, contacts 3 of relay PP complete a loop circuit to the test final over wipers +L and L and contacts 2 of relay: 1A operated. A condenser is bridged across these impulsing contacts 2 of relay 1A to reduce the sparking. The test circuit to the final selector extends from the ground at contacts 4 of relay 113, over contacts 4 of relay PP, the wiper P2, both windings of relay 2K, Fig. 2 the normal wiper N2, contacts 1 of relay 28 normal to relay 22. Relay 22 is provided with a noninductive winding which is extended through wipers 2UC2 and 2TC2 of the switches 2UC and 2T6 to contacts 1 of relay 22 normal to contacts 1 of relay 28. Relay 2K will no operate in series with the inductive winding of relay 22 and therefore the switch cannot be seized unless the final selector and control switches are normal. He lay 2A operates over the loop circuit already described and completes the obvious circuit for relay 2B. the .impulsiimrg is recommenced the relay 1A repeats each impulse to the relay 2A.. Relay 2A operates the switch 2T0 from ground, contacts 21 of relay 2A normal, contacts :2 of relay 28 pperated, contacts 22 i relay 2Kioperated, taots 1 of relay 27 normal, the windin of relay 23, contacts .1 of relay nonma, to the magnet of the switch "2T6. Relay 23 causes the partial operation of relay through contacts 3 of relay 125 normal, contldzs .1 of relay :23 operated. When the re lay 23 restores at the end of the digit the short-circuit is removed from the second winding of relay 25 which operates fully through contacts 4 of relay 225 operated to ground at contacts 2 of relay :22 operated. Contacts 2 of relay .25 close the driving circuit for the final selector magnet :32 over contacts 1 of relay 26 normal and contacts 3 of relay 2K operated. A marking ground is cxtmded from contacts f relay 526 normal contacts 5 of relay 2 operated, the wiper 2TC1 of the switch 2"rlC and a group marking wire, to a group manking Contact in the bank C of the selector and when the selector arrives in this position this ground isiexten'ded over contacts 4 of relay operatcd, contacts 3 of relay .26 normal, to the winding of relay and battery. The driving and marking circuit is independent of impulsing and the final selector may continue stepping during the time that the secand set of impulses are being a eoeived. When relay .26 does operate it provides at contacts 52 a locking circuit for itself to ground at contacts 2 of relay Contacts 1 of mlay125 switch the Limpulsing circuit to the magnet lof the switch QUC which .receives .the second set of impulses. The secand operation of relay 23causes the partial operation of relay 27 over contacts 3 of relay and contacts 3 of relay .27 when relay 23 subsequently releases relay :27 operates fully over its two windings inseries and its contacts 4. The driving circuit of the final selector magnet S2 is now reestablished I over contacts 1 of relay26 operated, contacts 2 of relay 27 operated, contacts 2 of relay 28 normal to ground. The marking circuit is re-established from ground at contacts 4 of relay 26 operated, contacts 5 of relay 27 operated, Wiper 2UC1 of the switch 2UC a units marking wire, control wiper C, contacts 4 of relay 2K operated, contacts 3 of relay 26 operated, to the Winding of relay 28 and battery. When relay 28 operates it opens the driving circuit of the magnet S2 at contacts 2 and the circuit for relays 2K and 22 at contacts 1 of relay 28.

Returningnow to the circuit of the test distributor it will be seen that during impulsing a circuit is recompleted for the relay E through contacts 4 of relay 1K normal, contacts 4 of relay RR normal, contacts 3 of relay 1B operated and contacts 1 of relay 1A normal to ground. Relay E com plot-es the obvious circuit for the relay TD and in this way a circuit is prepared at the end of impulsing for the relay RR via contacts 3 of relay E normal, contacts 490i relay TD operated, contacts 2 of relay PP operated, P1 wiper through the test final to the test wiper to test'the condition of the called subscriber. If this line is engaged there will be a ground potential which will cause the operation of relay. RR. Contacts 1 and 2 of relay RR reverse the battery to the Wire chief to signal that the called line is engaged. If the called line is free after aperiod relay TD will release and open the circuit of relay RR. VV'hen relay TD releases ground is extended through contacts 2 .irelay PC operated, contacts 1 of relay TD normal, "contacts 2 of relay PP operated to the P1 wiper causing the called line to test busy to other calls. The called subscribers lines are extended over the negative and positive test Wire +T and T to the wire chief for testing purposes, the co11- densers in these wires being shunted at contacts .1 and 2.' Facilities are provided to enable the wire chief to disconnect the positive wire thereby causing the release of the relay PC: the relay 1B remains operated due to relay 1A but the release of relay PC removes the ground from, the Wiper P1 thereby releasing the cut-oil relay of the called party. I

It will be seen that if the relay Riv. opcrate-d due to the called line being engaged, contacts 3 of relay RR will provide a looking circuit for relay TD which will maintain the circuit for relay RR :over contacts 4 of relay TD. Contacts ofrelay open the circuit of relay E to prevent that relay operating and thereby releasing relay lithe "wire chief desires to test other lines, -fiacilities are provided whereby furof relay 2B operated and contacts 1 of relay 2A normal. 'The impulsing will cause the operation of relay E and the distributor will test the new lines as already described. When the Wire chief releases relays 1A and PC release and a homing circuit is provided from the magnet through its interrupter spr'ings, contacts 2 of relay 113 normal to the ofi' normal wiper N1 and ground. The relapse of relays 2A "and 2Bat the test final switch closes a homing circuit forthis ill switch over contacts 3 of relay 2K, contacts 3 of relay 2B and the oft-normal bank N.

It is to be understood that the invention is not limited to the particular type and circuit arrangement of the conversation switches and control circuits described in detail. Modifications falling within the scope of the appended claims will readily occur, to those versed in the art. For example, instead of employing two marking switches in the control circuits for re sponding to the two-series of impulses, respectively, a single switch may be used which responds successively to the two series L of impulses and in accordance therewith first marks a group of lines and then a line within such group.

What is claimed is:

1. A telephone system comprising a test final switch, a plurality of test distributor switches, one of which is adapted to respond to transmitted impulses to select said final switch without performing any hunting operat-ion and wherein the circuit of said test distributor switch comprises an individual portion and a portion common to all of said distributor switches.

2. A telephone system comprising a plurality of test distributor switches, a test final switch adapted to set up a test connection to a subscribers line in response to transmitted impulses and wherein the circuit of said final switch comprises an individual portion and a portion common to said distributor switches.

3. A telephone system comprising a plurality of test distributor switches, a test final switch giving access to subscribers lines and adapted to be selected by said distributor switches, and a control circuit adapted to be operatively associated with any one of said distributor switches and which in response to transmittedimpulses is adapted to control the selective operation of said distributor switch.

4. A telephone system comprising a plurality of test final switches adapted to set up a test connection to a subscribers line, a control circuit adapted to be operatively associated with any one of said final switches and which in response to transmitted impulses is adapted to control the selective operation of said final switch. I

A telephone system comprising a plurality of test final switches adapted to set up test connectionsito subscribers lines, a control circuit common to said final switches, wherein one of said final switch es is adapted to be advanced initially to aparticular subscribers line under the control of said control circuit and subsequently to another subscribers line independently of said control circuit.

6. A telephone system comprising a test distributor switch, a test final switch, a control circuit for said final switch, said distributor switch. being adapted to efiect a testof the busy or idle condition of said final switch and said control circuit and to transmit a busy signalif said final switch or said control circuit is busy.

7. A telephone system according to claim 1 wherein said test distributor switch comprises means for making a test of the condition of the subscribers line to which connection has been made by the test final switch and for transmitting a busy signal in the event such line is busy.

- 8. A system according to claim 1 wherein said test distributor switch comprises a single test relay, said relay being adapted to make the test of the condition of the test final switches and of the lineselected by one of said final switches.

9. A system accordingto claim 1 wherein the subscribers line seized by the test final switch is marked busy to other final switches by a guarding potential applied to its test contact multiple from a point in the circuit of test distributor switch which selected said test final switch. I

10. A system according to claim 3 wherein said common control circuit is adapted to be automatically disassociated from said switch immediately the latter has been positioned.

11. A system according to claim 3 wherein said control circuit comprises an auxiliary switch adapted to respond to impulses and in accordance therewith to control the movement of said distributor switch.

12. A system according to claim 1 wherein said distributor switch comprises means for repeating impulses to said test final switch.

13; A system accordingto claim 1 wherein said distributor switch and said final switch are of the type having motion in one plane only.

In witness whereof, I hereunto subscribe my name this 20th day of December, 1929.

,; ESMOND PHILIP GOODWIN WRIGHT. 

